PC-DOS 320K format
The PC-DOS 320K format was one of several low-capacity 5 1/4" disk formats used on IBM PCs and compatibles in the early days of PC-DOS before the PC-DOS 360K format became the standard. It used a double-sided, double-density disk with 40 tracks per side with 8 sectors per track, and 512 bytes per sector. The disk turned at 300 RPM. These disks were generally used with FAT12 file systems under the MS-DOS or PC-DOS operating system, but (far more rarely) were used with other filesystems too (e.g CP/M-86). The sector headers, etc, were based on IBM 3740 format, albeit with MFM encoding (double density) replacing the original FM encoding (single density).
This format was the double-sided counterpart of the PC-DOS 160K format, but was soon superseded by the 360K format made possible by expanding the number of sectors per track to 9.
